This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-348529, filed Dec. 8, 1999; No. 2000-076684, filed Mar. 17, 2000; and No. 2000-078721, filed Mar. 21, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to an erecting type microscope and a transillumination condenser used therefor.
The present invention also relates to an optical element slider for an microscope.
As shown in FIG. 1, an erecting type microscope (prior art 1) having a transillumination is designed such that a space for a base portion 201, condenser portion 202, and stage portion 203 is ensured between the desk surface and a specimen. In general, the distance from the desk surface to the specimen is about 200 mm.
The base portion 201 needs to have a space for housing collector and relay lenses (not shown) for efficiently guiding light from a light source (not shown) to a specimen.
The condenser portion 202 needs to have a space for ensuring the stroke of vertical movement of a condenser 212 and the stroke of vertical movement of a stage 213 so as to easily interchange dedicated condensers corresponding to various types of microscopes such as a phase-contrast microscope and dark-field microscope or the magnification and type of an objective lens 211. In addition, the stage portion 203 needs to have a space for ensuring the rigidity of the stage 213.
In any case, a focusing handle 214 for focusing the microscope on a specimen and a stage handle 215 for adjusting the observation position of the specimen are disposed at distances of 60 to 80 mm from the upper surface of the table to allow the user to easily operate them while resting his/her hands on the table, minimizing occasions when he/she must move his/her hands in the air. The distance from the focusing handle 214 or stage handle 215 to the upper surface of the stage 213 is therefore set to 120 to 140 mm.
As a xe2x80x9cmicroscope with a focusing mechanismxe2x80x9d, a technique (prior art 2) is disclosed in Japanese Patent No. 2966514 (registered Aug. 13, 1999). FIG. 6 in this reference shows a revolver elevation type microscope whose object lens vertically moves. A stage 38xe2x80x2 is held on a stage support 41 fixed on the upper surface of the base. A condenser 39xe2x80x2 is also held on the stage support 41.
As an xe2x80x9coptical microscopexe2x80x9d, a technique (prior art 3) is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 7-174977. Referring to FIG. 7 in this reference, a mount portion 41 of a condenser unit is mounted with a gap with respect to a mount base 40 fixed to the upper surface of the microscope base, and the mount portion 41 can move in the range of this gap.
As a xe2x80x9can illumination optical system for a microscopexe2x80x9d, a technique (prior art 4) is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 7-56091. This optical system serves as a condenser optical system with a reduced distance from a light source to the position of a specimen. A relay lens for forming a light source image at the position of an aperture stop is divided into two parts, which are respectively disposed before and after a reflecting mirror.
The following problems arise in the above prior arts. In prior art 1, as shown in FIG. 1, when a specimen is to be replaced with another during observation, the user must release the focusing handle 214 or stage handle 215 and remove the specimen placed on the stage 213. The user then must place the next specimen on the upper surface of the stage 213.
In this case, if the focusing handle 214 or stage handle 215 is located far from the upper surface of the stage 213, the moving distance is long. In clinical examinations, an enormous number of specimens, i.e., several hundred to thousand or more specimens, are interchanged a day. If, therefore, the moving distance of the hand is long, fatigue builds up, and the user feels burdensome.
The shorter the distance from the focusing handle 214 or stage handle 215 to the upper surface of the stage 213, the better. In a conventional microscope in which the distance from the upper surface of the table to that of the stage is 200 mm, the moving distance is as long as 120 to 140 mm.
According to the arrangement of prior art 1, the upper surface of the stage 213 cannot be placed at a distance of about 130 mm from the upper surface of the table. The space for the base portion 201 may be reduced by placing, for example, a light-emitting flat plate using a fluorescent lamp or the like below the stage 213 or condenser 212 instead of sending illumination light emitted from the light source through the base portion 201. In this case, however, for example, the brightness decreases, and the requirement for the numerical aperture of the object lens cannot be satisfied. As a consequence, the illumination performance of the prior arts cannot be ensured.
In addition, since a field stop operation ring 216 is generally mounted on the upper surface of the base portion 201 below the condenser 212, the space for this component must also be ensured.
To reduce the space for the condenser portion 202, both the condenser portion 202 and the stage 213 may be lowered so as to reduce the space below the condenser 212. For this purpose, the stroke of vertical movement of the condenser 212 may be decreased. If, however, the stroke of vertical movement of the condenser 212 is decreased, limitations are imposed on the use of the condenser. For example, the condenser cannot be interchanged with another dedicated condenser corresponding to each type of microscope. This makes it impossible to satisfy the requirement for illumination performance.
Furthermore, if the space below the condenser 212 is reduced, the stroke of vertical movement of the state 213, i.e., the focusing guide stroke, is also reduced. To reduce the space for the stage portion 203, the stage 213 itself must be thinned, resulting in a deterioration in stage performance, e.g., a reduction in stage rigidity.
According to prior art 2, even in a revolver elevating type microscope, the condenser is laterally held by the stage support and spaced apart from the upper surface of the stage. It is therefore difficult to decrease the level of the specimen mount surface.
In prior art 3, although the condenser is directly mounted on the upper surface of the stage, a stage elevating scheme is used, and the condenser is designed to vertically move in almost the same stroke as the stroke of vertical movement of the stage to be interlocked with the vertical movement of the stage. This makes it impossible to decrease the level of the specimen mount surface.
In prior art 4, the operation/effect of setting the specimen mount surface at a position lower than the upper surface of the table by using an optical system for reducing the distance from the light source and the specimen is disclosed. However, the arrangement of an actual microscope is not disclosed.
The optical element slider of a conventional microscope will be described next with reference to FIG. 2. In a microscope 331 capable of switching various observation methods, a turret 333 incorporating optical elements 332 such as ring slits is rotatably supported below a stage 340 of the microscope body to easily switch between a bright-field observation and a phase-contrast observation and between a bright-field observation and a dark-field observation.
To change the observation method, the turret 333 is turned to change an optical element 333 on the optical axis.
A base 341 of the microscope body has ND filters 334a and 334b for adjusting the brightness of illumination light independently of the optical elements 332, and a filter inserting/removing unit 335 for inserting/removing the filters, thereby allowing the observer to insert/remove filters as needed.
In a phase-contrast observation and dark-field observation, since a specimen is illuminated through a ring slit, only part of the specimen is illuminated, and hence the visual field becomes dark. In switching from a phase-contrast observation to a bright-field observation or from a dark-field observation to a bright-field observation, since the illuminance difference in the visual field is large, the ND filter 334a or 334b is inserted during a bright-field observation or the brightness of the light source is adjusted by operating a dimmer volume 336 of a dimmer.
In this case, in addition to the ND filters 334a and 334b, an interference filter for increasing the contrast in a phase-contrast observation and a daylight filter for matching color temperatures in a bright-field observation or photographing operation are used. In addition, a polarizing plate is sometimes placed on the filter frame in a polarization observation.
According to the conventional microscope described above, since the optical element slider formed by the turret 333 and the filter attaching/detaching unit 335 are discrete components, switching requires different operations. In a case wherein observations must be frequently switched as in the following case, very complicated operations are required.
{circle around (1)} In switching between a phase-contrast observation and a bright-field observation, since the field illuminance difference is large, an ND filter is inserted in a bright-field observation.
{circle around (2)} In switching between a phase-contrast observation and a bright-field observation, an interference filter is inserted to increase the contrast in a phase difference observation, and an ND filter or daylight filter is inserted in a bright-field observation.
{circle around (3)} In switching magnification between phase-contrast observations, since many phase-contrast optical elements are dedicated ones corresponding to different magnifications, optical elements are also switched in accordance with a change in magnification. At the same time, as objective lens are interchanged and optical elements are switched, the field illuminance changes. To suppress this change, an ND filter is inserted.
{circle around (4)} In switching between a dark-field observation and a bright-field observation, since the field illuminance difference is large, an ND filter is inserted in a bright-field observation.
In some case, to adjust the field illuminance, the user operates the dimmer volume 336 instead of inserting an ND filter.
In addition, in a bright-field observation, an aperture stop 337 must be operated in accordance with the numerical aperture of the objective lens. In a phase-contrast observation or dark-field observation, the field stop must be opened.
In this case, the optical element slider and aperture stop 337 are discrete components. For this reason, every time a bright-field observation and phase-contrast or dark-field observation are switched, the user must operate the aperture stop 337 as well as switching filters.
To solve the above problem, the optical element slider and the filter frame or aperture stop may be interlocked with each other. This, however, leads to an increase in the number of components or the complexity of the mechanism. As a consequence, the cost increases or the overall size of the microscope increases.
According to a known arrangement, filters are automatically (electrically) switched or the intensity of light is automatically adjusted in accordance with a switched optical element. This arrangement, however, requires a sensor, monitor, electrical components, and the like, resulting in a great increase in cost.
The present invention has been made in consideration of the problems in the prior arts described above, and has as its object to provide a compact, inexpensive, easy-to-operate microscope which can shorten the distance from the stage handle to the upper surface of the stage and maintain illumination performance equivalent to that of the prior arts.
It is another object of the present invention to provide a microscope having high operability, a simple arrangement, and a compact optical element slider, which allows optical components such as optical elements and filters to be simultaneously switched by one switching operation.
It is still another object of the present invention to provide a transillumination condenser which can be mounted in the microscope.
In order to achieve the above objects, according to the first aspect of the present invention, there is provided a microscope having a mirror for deflecting light from an illumination light source in a direction of an objective lens and illuminating a specimen via a condenser lens disposed above the mirror, comprising: a stage support which is mounted on an upper surface of a base portion of the microscope to fix a stage, on which a specimen is placed, with respect to an optical axis direction of the objective lens; a condenser body mounted on the upper surface of the base portion of the microscope; a condenser lens holding member which holds a condenser lens and which is supported by the condenser body; an elevating mechanism which vertically moves the condenser lens holding member; and a focusing mechanism which moves the objective lens in the optical axis direction.
According to the second aspect of the present invention, there is provided a microscope defined in the first aspect, wherein the stage support has a cantilever structure mounted on the base portion.
According to the third aspect of the present invention, there is provided a microscope defined in the first aspect, wherein the condenser lens holding member is rotatable with respect to the base portion, and the condenser lens can be removed from an illumination optical path by rotating the condenser lens holding member.
According to the fourth aspect of the present invention, there is provided a microscope defined in the first aspect, wherein the microscope further comprises a fixed frame mounted on the base portion, a centering frame which is mounted on the fixed frame to center the condenser lens, and an aperture stop mounted on the centering frame, the elevating mechanism comprises a fixed guide integrally formed on the centering frame and mounted along a side surface of the base portion, and a movable guide mounted to be movable with respect to the fixed guide, and the condenser lens holding member is mounted on the movable guide.
According to the fifth aspect of the present invention, there is provided a microscope defined in the first aspect further comprising an optical element slider which has at least two light beam through holes and can selectively insert one of the light beam through holes in an optical axis of an optical device, the optical element slider mounting and stacking an optical element having a pupil modulation function and an optical component having no pupil modulation function in the optical axis direction in each of the light beam through holes.
In the microscope according to the fifth aspect, the stage is permanently held on the stage support mounted on the upper surface of the base portion, and the condenser lens and its holding members are disposed on the upper surface of the base portion inside the stage and stage support, thereby making the illumination optical system low while maintaining the same illumination function as that of the prior art. In addition, even if the focal position of the condenser deviates due to a change in the thickness of a specimen or the like, the focal position can be adjusted by using the elevating mechanism for the condenser lens holding member for holding the condenser lens.
In the microscope according to the fifth aspect, the optical element slider may be designed such that in the respective light beam through holes, optical elements each having a pupil modulation function are mounted on the upper surface of the optical element slider, while optical components having no pupil modulation function are inserted in the opening portions formed in a side surface of the slider and mounted therein.
In the microscope according to the first aspect, the stage is permanently held on the stage support mounted on the upper surface of the base portion, and the condenser lens and its holding members are disposed on the upper surface of the base portion inside the stage and stage support, thereby making the illumination optical system low while maintaining the same illumination function as that of the prior art. In addition, even if the focal position of the condenser deviates due to a change in the thickness of a specimen or the like, the focal position can be adjusted by using the elevating mechanism for the condenser lens holding member for holding the condenser lens.
In the microscope according to the second aspect, in addition to the above effects, since the stage support has a cantilever structure mounted on the base portion on the back side of the condenser body, the respective members of the transillumination condenser can be housed and interchanged in the space secured by the cantilever structure.
In the microscope according to the third aspect, in addition to the above effects, since the condenser lens holding member is rotatable and the condenser lens can be freely inserted/removed in/from the illumination optical path, even if objective lenses having different magnifications are interchanged, the condenser lens can be easily inserted/removed in/from the illumination optical path within a narrow space.
The microscope according to the fourth aspect comprises the fixed guide integrally formed on the centering frame and vertically extending along the side surface of the body base portion, the movable guide movably supported on the fixed guide, the lens holding frame supported on the movable guide, the condenser lens group mounted on the lens holding frame, and the moving mechanism for vertically moving the movable guide. With this arrangement, a sufficient guide length can be secured, with which the condenser lens group is vertically moved by the fixed and movable guides, to realize stable operation, and a large space for operation can be ensured.
According to the microscope of the fifth aspect, there is provided a compact optical element slider with high operability and a simple arrangement.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.